Yarn degradation testers

ABSTRACT

AN APPARATUS AND A METHOD FOR MEASURING THE TENSILE STRENGTH OF THE CONSTITUENT YARNS OF A FABRIC MATERIAL WHEREBY THE YARN WHICH IS BEING TESTED IS MOVED SUBSTANTIALLY AT RIGHT ANGLES TO THE AXIS THEREOF BY YARN ENGAGING MEANS AGAINST A RESTRAINING FORCE EXERTED BY A MATERIAL ENGAGING MEANS WHICH CONTINOUSLY ENGAGES ONE SURFACE OF THE MATERIAL BEING TESTED, WHILE THE FORCE APPLIED TO THE YARN IS BEING MEASURED.

Feb.' 2, 1971 .1.1 Rl MCDWELL. l I :YARN DEGRDTION TESTERS 4Filed sept. e,

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109 ,11o V11a i I i////K///// United States Patent O York Filed Sept. 6, 1968, Ser. No. 757,894 Int. Cl. G01n 3/14, 3/20 U.S. Cl. 73-95.5 7 Claims ABSTRACT OF THE DISCLOSURE An apparatus and a method for measuring the tensile strength of the constituent yarns of a fabric material whereby the yarn which is being tested is moved substantially at right angles to the axis thereof by yarn engaging means against a restraining force exerted by a material engaging means which continuously enages one surface of the material being tested, while the force applied to the yarn is being measured.

BACKGROUND OF THE INVENTION This invention relates to the measurement of tensile strength of a constituent yarn of fabric material. By the term fabric material is meant those materials which comprise yarns. Such yarns may be merely a parallel array or may, for4 example, have been woven or knitted. IEach yarn may comprise an assemblage of fibers or filaments, either natural or man-made, twisted together to form a continuous strand. In the alternative, each yarn may be a monoilament. By the use of the word yarn it is also meant to include wire strands, either multilament or monolament, or any combination of any of the above. In short, the yarn may be any strand-like material.

. In many applications it is desirable to be able to determine the amount of useful life remaining in a fabric material. For example, it would be useful to be able to determine the amount of life remaining in an industrial conveyor belt, or an endless cloth used in several places in paper manufacturing machinery. In either of these cases, should the fabric unexpectantly fail and tear off the machinery during operation, there would probably be an unscheduled shutdown of that machine. In addition, severe machine damage might occur. The useful life of the endless cloths used in the manufacture of paper, for example, may be limited by virtue of loss of strength by its individual yarns. These cloths are usually woven from yarns comprising natural fibers, synthetic fibers, wire strands, or combinations thereof. Yarn strength decreases from wear, chemical, and thermal degradation during field use of the fabric and eventually reaches a point where continued operation of the fabric is not desirable. Obviously, it would be desirable to be able to determine accurately when that point will be reached. The present invention achieves this objective by providing means for measurement of the tensile strength of the constituent yarns of the cloth from which the physical condition, and therefore the remaining usefulness of its fabric can be ascertained through use of the invention disclosed herein. Moreover, this determination can be made quickly, Without removing the cloth from the machine.

Accordingly, it is an object of this invention to provide a means to determine the amount of useful life remaining in a fabric material.

It is another object of this invention to provide a means to determine the tensile strength of individual yarns in a fabric material.

Still another object of this invention is to provide a portable means for measuring tensile strength of individual yarns in a fabric material.

Yet another object of this invention is to provide a means whereby tensile strength of individual yarns in a fabric material may be recorded.

SUMMARY OF THE INVENTION This invention achieves these and other objects, which will be readily apparent to those skilled in the art, by providing a yarn degradation tester comprising material engaging means for continuously engaging one surface of the material being tested, and tension means for applying tension to the yarn, the tensile strength of which is being measured, comprising yarn engaging means for engaging the yarn and moving it substantially at right angles to the axis thereof against the restraining force of the material engaging means, and means for measuring the amount of force to which the yarn is subjected.

DESCRIPTION OF THE DRAWINGS This invention may be clearly understood by reference to the attached drawings in which:

FIG. l is a cross-sectional view of one embodiment of this invention.

FIG. 2 is a cross-sectional view through the plane 2-2 in FIG. 1.

FIG. 3 is a plane view of another embodiment of this invention, and

FIG. 4 is a cross-sectional view through the plane 4-4 in FIG. 3.

FIGS. 1 and 2 illustrate one embodiment of this invention. Its elements include a handwheel 102 attached to an actuating column 104 by 4means of set screw 105, actuating column 104 being rotatably affixed to housing 100 by means of handwheel 102, bearing 106, and column lip I109. Threaded spindle 110 extends into housing 100 and mates with actuating column 10'4 by means of threaded insert 108 which is affixed within actuating column 104. Rib 116 of spindle 110 engages actuating probe 122 of tension recording device 124. A faceplate 120 having an aperture therein is attached to housing As can be seen from FIGS. 1 and 2, actuating column 104 is substantially hollow. Accordingly, as actuating column 104 is rotated relative to housing 100, by means of handwheel 102, threaded spindle is drawn up into actuating column 104 as a result of the interrelationship between threaded spindle 110 and thread insert 108. The rotation of spindle 104 is facilitated by means of bearing 106. Rotational movement of spindle 110 is eliminated by means of rib 116 and its mating relationship with slot 118 of housing 100.

In operation, spindle 110 is hooked to the yarn which is to be tested by means of hook 114, hook 114 being attached to spindle 110 by means of jam nut 112. By rotating handwheel 102, threaded spindle 110 and the yarn attached thereto is drawn into housing 100. Subsequently, faceplace 120 is held in face-to-face relation to the material being tested and the rotation of handwheel 102 is continued. As can be seen from FIG. 1, the drawing of spindle 110 into housing 100 will cause rib 116 to move actuating probe 122 along slot 118, thereby actuat ing tension recording device 124. In order to obtain ank accurate reading of the amount of tension applied to the yarn, it is necessary that the reading device (not shown) positioned within tension recording device 124, be adjusted so that it will be positioned at zero when the application of tension to the yarn begins. From FIG. 2, it can be seen that the mating of rib 116 and slot 118 precludes rotational movement of spindle 110. In this manner yarn 126, the yarn which is being tested, is not twisted as it is drawn substantially at right angles to the axis thereof into housing 100. By the term axis is meant a fictitious line representing the general longitudinal orientation of the yarn. Thus, for a straight yarn, the axis is the true axis of the yarn. For a sinusoidally undulating yarn, it is the axis about which the yarn undulates. For intermittently undulating yarn (such as one in a satin weave of more than two harnesses) the axis is the fictitious line represented by joining together the yarn axes in their straight portions. Rotational movement of spindle 110 can also be eliminated by use of a slotted spindle and ribbed housing, for example.

Though FIG. 1 depicts a material engaging means, a yarn engaging element and an actuating means as a single assemblage of parts, the present invention also contemplates an interrelationship of individual units. For example, the material engaging means might be separate from the yarn engaging element and actuating means. In this manner, the material engaging means could be held in position by one person, While someone else operated the yarn engaging element and actuating means for moving the yarn engaging element substantially at right angles to the axis of the yarn against the restraining force of the material engaging means.

DESCRIPTION OF PREFERRED EMBODIMENT The embodiment of this invention which is illustrated in FIGS. 3 and 4 is one which is particularly suited for achieving the objects of this invention. By means of this embodiment, the measuring of yarn tensile strength is solely dependent upon the force applied to the yarn, yarn elongation being substantially accounted for by means of a helical spring, for example. Scale adjustments within recording device 221 to take into consideration yarn elongation need not be made, since recording device 221 will only be actuated when yarn 249, the yarn which is being tested, is subjected to tension by means of helical spring 230, for example. Its elements include a handwheel 202 attached to an actuating column 204 by means of set screw 206. Actuating column 204 is movably interconnected with scale actuator 208 so that actuating column 204 can be rotated by means of handwheel 202 without causing scale actuator 208 to rotate. Scale actuator 208 extends through an aperture in collar 210 and into housing 212 where it engages recording device 221. Collar 210 is attached to housing 212 by means of screw 214. Alternatively, actuating column 204 could act as a scale actuator, scale actuator 208 being discarded. However, in this embodiment of the present invention a two-piece assembly is used as noted above. Spindle 216 extends through an aperture in plate 218 and into housing 212 where it mates with actuating column 204.

Referring to FIGS. 3 and 4, it will be seen that actuating column 204 is substantially hollow, having aixed therein threaded insert 226, and is maintained in face-toface relationship with bearing 228 by means of helical spring 230. Actuating column 204 extends into, and is rotatably interconnected with, scale actuator 208, being spaced therefrom by means of shaft bearings 232 and wave washer 234. Head bearing 236 is positioned between handwheel 202 and scale actuator 208 to facilitate the turning of handwheel 202 relative to scale actuator 208. Scale actuator 208, which actuates scale indicator 220 by means of its engagement with actuating probe 238, is disposed in spaced relationship from collar 210 by means of O-rings 240. Guide insert 242 is positioned within housing 212 to properly guide spindle 216 into housing 212 in such a manner that spindle 216 mates with actuating column 204. In addition, guide insert 242 supports spring 230 by means of spacer 244. Spindle 216 can be removed from housing 212 by turning handwheel 202 counterclockwise, thereby disengaging spindle 216 from actuating column 204. In this manner the hooking of yarn 249 to spindle 216 by means of hook 248 may be facilitated.

As can be seen in FIG. 4, after inserting spindle 216 through the aperture in plate 218 and into housing 212 until it contacts threaded insert 226, spindle 216 can be mated with actuating column 204 merely by turning handwheel 202 so that the threads of threaded insert 226 mesh with the threads of spindle 216. It should be noted, however, that spindle 216 can be movably interconnected with actuating column 204 by means other than threads. For example, spindle 216 could have a continuous helical groove extruded therein which could mate with a rib provided within hollow actuating column 204. By further turning handwheel 202, spindle 216 will be drawn into housing 212, actuating column 204 being held in position by spring 230. However, if a constituent yarn of a fabric material is hooked to spindle 216 by means of hook 248, hook 248 being attached to spindle 216 by means of jam nut 250, then the resistance offered by the yarn to the upward movement of spindle 216 will cause actuating column 204 to bear upon and thereby compress spring 230, and move downward relative to spindle 216. As a result of the interrelationship between scale actuator 208 and actuating column 204, scale actuator 208 will also move downward relative to spindle 216, and as a result of its interrelationship with recording device 221, scale actuator 208 will bear upon actuating probe 238 thereby causing scale indicator 220 to slide down groove 258, actuating probe 238 being attached to scale indicator 220 by means of screw 252. When the yarn breaks as a result of the tension applied thereto by means of compressed spring 230, scale actuator 208 and actuating column 204 will slide upward relative to spindle 216 since the expansive forces of spring 230 are greater than the pressing force of actuating column 204.

The operation of the embodiment of this invention which has heretofore been set forth will now be described referring to FIGS. 3 and 4. Scale indicator 220 is slid upward along slot 258 as far as it will go. Spindle 216 is removed from housing 212 by turning handwheel 202 counterclockwise until actuating column 204 is disengaged from spindle 216. At this point, spindle 216 can be pulled out of housing 212 and the yarn which is to be tested hooked to spindle 216 by means of hook 248. Subsequently, spindle 216 is re-inserted through aperture 254 in plate 218 and into housing 212 until spindle 216 contacts actuating column 204, at which time handwheel 202 is turned clockwise so that spindle 216 and actuating column 204 mesh one with the other in threaded engagement. In the alternative, the yarn may be hooked to spindle 216 while spindle 216 is still engaged with actuating column 204. By holding plate 218 firmly against the fabric material being tested and continuing turning handwheel 202 clockwise, the yarn being tested is drawn into housing 212. Simultaneously, helical spring 230 is compressed by means of actuating column 204, and scale actuator 208 is caused to bear down upon actuating probe 238, thereby causing scale indicator 220 to slide downward along slot 258 until the yarn breaks, the tensile strength thereof being indicated by means of hairline 224. In this manner yarn tensile strength is measured independent of yarn elongation; i.e., yarn tensile strength is solely dependent upon the force applied to the yarn. By using helical spring 230, tension may be accurately translated into and measured in terms of the linear displacement represented by the degree of compression of the spring 230.

Similar results could be achieved by using other spring means. For example, a resilient material such as rubber could be used in place of helical spring 230. Similarly, a cylinder having a predetermined amount of air pressure therein, or a pneumatic cylinder, could be used in place of helical spring 230.

By using a recording device of the design in which the scale indicator stays at the position reached when the yarn breaks, readings so obtained may be preserved for recording. Such a result may be achieved, for example, through use of a mechanism such as shown in FIGS. 3 and 4 wherein scale indicator 220 is rigidly held in slot 258 by means of screw 252 and spacer 256. As can be seen from FIG. 4, actuating probe 238 extends into a slot 222 within housing 212 and is connected to scale indicator 220 by means of screw 252. Scale indicator 220 is disposed in spaced relationship from housing 212 by means of spacer 260 and wave washer 262. Plate 264 encloses recording device 221 by means of screws 266'.

By using a spindle which mates with insert 242, rotational movement of the spindle can be eliminated, thereby adding to the accuracy of the measurement of tensile strength. Such a result may be achieved, for example, through use of a mechanism such as shown in FIG. 4 wherein spindle 216 has a rib 217 which mates with slot 243 of insert 242. In the alternative, a spindle could be used which mated with housing 212, insert 242 being eliminated.

The embodiments which have been described herein are but some of several which will utilize this invention and are set forth here by way of illustration, but not of limitation. It is apparent that many other embodiments which will be readily apparent to those skilled in the art may be made without departing materially from the spirit and scope of this invention.

I claim:

1. An apparatus for measuring the tensile strength of a constituent yarn of fabric material, comprising a material engaging means for engaging one surface of said material' continuously while said measurement is being made, and tension means moveably interconnected to said material engaging means for applying tension to said yarn, said tension means comprising a yarn engaging means for fixedly engaging said yarn and moving same substantially at right angles to the axis of said yarn against the restraining force effected by the engagement of said material engaging means with said material, and means for measuring the amount of force which is applied to said yarn by said yarn engaging means.

2. The device described in claim 1 wherein said tension means comprises an actuating means engaging both said material engaging means and said yarn engaging means for imparting to said yarn engaging means, substantially at right angles to the axis of said yarn, motion relative to said material engaging means against the restraining force of said material engaging means.

3. The device described in claim 2 wherein means are provided for guiding said yarn engaging means in mating alignment with said actuating means and along the path of motion substantially at right angles to the axis of said yarn without rotational movement of said yarn engaging means.

4. The device described in claim 2 or 3 wherein said actuating means is irnpelled away from said material engaging means by a spring means which also provides the means for imparting and maintaining tension to said yarn.

5. The device described in claim 4 wherein said spring means comprises a helical spring.

6. The device described in claim 5 wherein said yarn engaging means is a threaded shaft with a hook at one end whereby said yarn may be engaged with said yarn engaglng means.

7. An apparatus for measuring the tensile strength of a constituent yarn of fabric material comprising:

(a) a housing having a collar attached to one end thereof and a faceplate attached to the other end thereof, said collar and said plate each having an aperture therein,

(b) a hollow scale actuating device disposed in mating relationship with said housing and extending through said aperture in said collar into said housing,

(c) an internally threaded actuating column rotatably afxed to said scale actuating device,

(d) a handwheel attached to said column,

(e) a tubular guiding element axed to said housing and disposed therein between said plate and said column, the opening in said element being aligned with said aperture in said plate and said actuating column, said element having a slot therein extending in a direction substantially normal to said plate,

(f) a helical spring for moving said column substantially at right angles to the axis of said yarn, said spring disposed between said element and said column, the center of said spring aligned with said opening in said element and said column,

(g) a threaded cylindrical yarn engaging spindle for ixedly engaging said yarn having a hook attached to one end thereof and having a rib protruding from said one end for mating with said slot when said spindle is inserted through said apertures in said plate and said element, through the center of said spring, and aflixed to said column within said housing by means of said threads,

(h) a recording device attached to said housing and having an actuating probe engaging said scale actuating device.

References Cited UNITED STATES PATENTS 169,376 10/1875 Scott 73-95 174,496 3/1876 Dimock 73-95 1,031,208 7/1912 Thompson 73-144 1,277,874 971918 Crowell 73-144 1,833,195 11/1931 Albright 73-144 2,242,083 5/ 1941 Naumann 73-95 RICHARD C. QUEISSER, Primary Examiner I. WHALEN, Assistant Examiner U.S. Cl. X.R. 73-144 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 I559 470 Dated Eghrnm! 2 Q1] Inventor(s) John R. McDowell It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column l, line 17, "enagesl should read engages Column 4, line 63, after "air", insert or fluid Signed and sealed this 12th day of December 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GoTTscHALK Attesting Officer v Commissioner of Pate! 

